99 Fisher Paragon & 06 Fisher Tassajara options

Howdy folks-

I'm about to start work on a couple projects, and thought I'd ask your input before diving in.

On hand, I've got an 06 Tassajara finished out in LX, with a manitou Axel fork. Nothing fancy, its 100% stock as far as I know.
I've also got a 99 Paragon frame, with nothing on it.
Finally, I've got a trek 3500, beat to hell, that I am planning on using for parts. Its got a rigid fork, a quill-type stem, and some decent V-brakes and wheels.

My plan is to take the components from the Tassajara and throw them on the Paragon. Being a semi-race-worth frame, I figure the Paragon will end up being a better handler and maybe a bit lighter weight. The only issue here is that the headtube is a bit shorter, so I'll probably need to pick up an extra spacer for it. No big deal. I think this will come together nicely, but can anyone tell me if its worth doing? the Paragon's geometry seems a little more aggressive, and it looks like there might be disc mounts on back, which would be nice.
Next, I'd turn the Tassajara into a SS by pulling apart the 3500. I was planning on using the rigid fork, and a headset from another bike to put it together. If I had to use the headset from the 3500 (quill-style, remember) I'd have to have the fork shortened. Other than that, would I run into any issues?